Chloroprene rubbers are used in automobile parts such as transmission oil cooler hoses and power steering hoses, and industrial rubber parts of which oil resistance is required such as various hoses. On the other hand, ethylene-α-olefin-nonconjugated diene-based rubbers are used in automobile parts such as weather strips, radiator hoses and brake parts, and industrial rubber parts of which heat resistance is required such as window frames and heat-insulating materials.
The performance required of the industrial rubber parts as described above has been increasing year after year, and studies for meeting the required performance have been made.
In Patent Literature 1, a rubber composition is described which is prepared by blending predetermined amounts of a thiazole compound, a thiuram compound and a thiourea compound into a chloroprene rubber composition comprising 100 parts by weight of a chloroprene rubber and 5 parts by weight or more and 45 parts by weight or less of an ethylene-propylene-diene copolymer rubber.
In Patent Literature 2, a rubber composition is described which is prepared by adding an organic peroxide and a thermosetting prepolymer to a copolymer rubber in which ethylene, an α-olefin and 5-ethylidene-2-norbornene are essential constituents.